U.S. Provisional Application No. 61/273,720, filed Aug. 7, 2009, is incorporated herein by reference in its entirety.
Presently, there is an increased demand for corn cobs as a feedstock for cellulosic ethanol, as well as other uses. As a result, there is heightened interest in collecting corn cobs during corn harvest. There is also concern by some that cob collection may reduce soil nutrient content. In this regard, crop residue or stover, e.g., corn stalks, leaves, husks and cobs, are traditionally left on the field after harvest, and break down over time to replenish soil nutrients. If a component of the residue, e.g., cobs is instead collected, nutrient levels could be lowered as a result. To mitigate this concern, some consider it desirable when collecting cobs, to collect mainly only the cobs, and leave the other residue of the harvesting operation, e.g., lighter residual husks and leaves, on the filed with the stalks. Thus, it is sought to have a cob conveyor system adapted for operation in connection with a corn harvester, which incorporates an ability to separate or clean the cobs from the other lighter residue, and return the other residue to the field or another location. It is also desirable for the collected cobs to be compact, e.g., without loose husks, leaves and the other residue, so as to increase the amount of cobs that the collection device and subsequent containers can hold. Still further, for some techniques for producing ethanol from corn cobs, the presence of substantial amounts of other residue, e.g., loose husks and the like, is undesired, and for a load of cobs of a given volume, the amount of compensation paid will be reduced if significant residue is present. Also in this regard, the producer, e.g., farmer, may be required to pay transportation costs for the cobs, and if significant other residue is present, the farmer will be paying to transport materials for which no compensation is received and the unwanted residue material will displace wanted cobs in the transported loads.
Numerous apparatus have been proposed for use in connection with cob collection devices, for cleaning or separating cobs from the other residue. To illustrate, prior to the early 1960's, the common corn harvesting practice involved picking the ears of corn in the field, removing husks from the ears, and transporting the ears still containing the corn kernels to a corn crib, and later shelling the corn off of the cobs at a stationary sheller. This harvesting procedure has been almost entirely replaced by modern self-propelled combine type harvesters, which separate and collect the corn kernels, and discharge the cobs and other stover onto the field.
More recently, a variety of devices have been proposed for harvesting and cleaning cobs. Reference in this regard, Flamme, U.S. Pat. No. 5,941,768, issued Aug. 24, 1999; Redekop et al., U.S. Patent Publication No. 20090095662 A1, published Apr. 16, 2009; Redekop et al., U.S. Patent Publication No. 20090104952 A1, published Apr. 23, 2009; and Redekop et al., U.S. Patent Publication No. 20090124309 A1, published May 14, 2009, which variously propose cob and residue conveyor systems with apparatus for blowing or sucking air upwardly through a flow of corn residue falling over the end of a conveyor or conveyors.
Some embodiments disclosed in the above referenced patent and publications utilize fans located below the falling residue and operable for directing flows of air upwardly therethrough for carrying the lighter residue upwardly and into a hood that then directs the air and residue downwardly beside the apparatus to the field. However, observed shortcomings of these embodiments include that the air flows generated must be sufficiently powerful to blow through the falling cobs and lift the other residue and carry it upwardly, then change direction to carry it downwardly. The blower fans for accomplishing this are also located beneath the conveyors, such that heavier material can fall into the blower fans or cover grates covering the fans, to impede operation thereof and possibly cause damage thereto. There is also no provision disclosed for directing the residue onto the field below the apparatus, such that uneven residue coverage can result.
Other embodiments disclosed in the above references utilize air plenums having discrete nozzles directed for discharging air flows upwardly into the falling corn residue for separating the lighter residue from the falling cobs. Observed shortcomings of these arrangements include that there will be regions of the crop residue flows between the nozzles that will not be adequately covered. And it is possible that the flow from the nozzles will be inadequate to lift and carry the residue from the cobs. It is also observed that the nozzles may become clogged and require servicing.
In another embodiment of the above references a fan located above or beside the conveyors sucks the lighter residue from the cobs. However, again, the residue must be lifted. Also, the residue must pass through or be diverted from the fan. And, if the fan is located only on one side of the apparatus, the residue will be discharged to one side only, resulting in uneven coverage.
Thus, what is sought is a cob conveyor system which incorporates a cleaning capability for operation in association with a conveyor harvester, which provides one or more of the capabilities, namely, positively separating husks and other lighter elements of corn residue from the cobs, and which overcomes one or more of the shortcomings and disadvantages, set forth above.